There are some benefits to metal music like the fact that it is cathartic in nature. It helps in purging the wrath and fascination with evil that is inherent in human beings. It also helps in communicating extreme emotions. There is a whole gamut of emotions in metal songs from giddy joy, to adventure, to righteous anger to haunting fears. The only emotions that this genre of music does not portray include boredom, complacency and dull stupidity.
Some people consider metal music to be all about chaos and destruction. But the fans of this genre of music do not think so. Of course some of the death metal and black metal music may be chaotic but most of the music is well-structured even if it is extreme. At the same time, even chaotic music is not destructive in its purpose, instead it is more cathartic in nature. It gives vent to our nihilist urges and hence purges them.
Overall heavy metal is a positive expression of negative emotions, but it is not meant for everyone. Due to the fact that heavy metal portrays extreme emotions it is not meant for people who do not identify with such emotions. Such people will not enjoy heavy metal music. All in all although the popularity of heavy metal is diminishing due to the ever evolving music scene, there are still aficionados who will swear by it.